Back hatch will not lock on 2006 Chevrolet Tahoe

Just purchased a 2006 tahoe and the back hatch does not want to lock. What to do and how to fix this problem.

2 answers
The latch assembly has probably failed, Stop by your local body shop and have them order a latch and replace it
I had the same problem with mine. I found one on ebay for about half price of a new one and all works well now.